Display screen or portion thereof with transitional graphical user interface



FIG. 1 is a front view of a display screen or portion thereof with transitional graphical user interface showing the first image in a sequence;

FIG. 2 is a front view of the second image included in the sequence; and,

FIG. 3 is a front view of the third image included in the sequence.

The longer-incremented broken lines showing of a portion of a display screen of a communications terminal illustrate environment and form no part of the claimed design. The medium length broken lines show a border of the claimed design. The images and text shown in finer-incremented broken lines illustrate features that form no part of the claimed design.

The greyscale in the drawings indicates a contrast of appearance.

The subject matter in this patent includes a process or period in which an image changes into another image. The process or period in which an image transitions to another image forms no part of the claimed design. 

CLAIM The ornamental design for a display screen or portion thereof with transitional graphical user interface, as shown and described. 